For
the plants and animals that thrive where ocean meets
land, the world is a rough-and-tumble place.

By
Paul VanDevelder/Photo by Art Wolfe

Pocket universe: Relatives of every major group of
invertebrates on earth are represented in a single tidepool.

Early one summer morning, while balanced on a knife's edge of basalt
high above the churning surf at land's end, I was momentarily seized by
an urge to leap. Gulls, suspended all around me in effortless flight,
seemed to mock my hesitation. After a paralyzing heartbeat of indecision,
I stepped back. The ocean roared. Green Pacific surf exploded against
the volcanic ramparts, pelting me with spray and an unbidden epiphany.
Coming back to the sea is always the return ticket on a round-trip journey
that began long before my birth. As I sorted through my wits, a familiar
voice boomed from the eddies of ground fog that swirled across the cobbled
beach, far below. "Yo, hey!" hollered my guide, John Borowski,
a science teacher from Salem, Oregon. Borowski's roots were yanked out
of the New Jersey shore 15 years ago, then repotted in the Pacific Northwest.

His grin flashed a thin white line of teeth as he pointed with animated
excitement at something in his bearlike paw. "You've gotta see this!"

At first light on a clear June day, Borowski and I had arrived at Yaquina
Head on the central Oregon coast. We weren't alone. The stream of headlights
following us off U.S. 101 suggested a parade of Shriners looking for breakfast.
In fact, none of us had met before. We were scientists and painters, photographers,
teachers, and families from as far away as Nebraska and Colorado. What
prompted our coincidental odyssey was a phenomenon Borowski calls a "monster
minus," a huge tidal swing caused by an ephemeral gravitational alignment
of earth, moon, and sun.

For the family of Cornhuskers, the trek to Oregon was old hat. As we
set off down the narrow goat path that switchbacked across sheer-walled
cliffs to the tidepools, hundreds of feet below, they told me this was
their third trip to Oregon in as many years. Each January they sat around
their kitchen table in Nebraska and scheduled their annual vacation to
coincide with the deepest dip on the tide charts. This year it would be
a minus-two-and-a-half-foot "event" beginning at 6:30 on a morning
in late June, on a beach 1,500 miles away.

For marine scientists this was The Big Moment, a fleeting glimpse into
the cauldron of our planet's oldest and most vital soup kitchen. For all
but a few hours of the year, the lower reaches of that kitchen are fiercely
hostile to hominids in sneakers. Yet for all of earth's pelagic species,
all the free-swimming Nemos out there, the intertidal zone is a prodigious
protein factory, the great seaside takeout window on which all these species
depend for survival. Each echinoderm, for example, in a thriving community
of thousands of echinoderms, or sea stars, releases several million eggs
every time it spawns. A handful of those eggs will ripen in the dim solitude
of the deepest region of the intertidal zone and become new members of
the community. The remaining millions, a wave of protein and lipids, will
be carried off by the churning surf to dozens of hungry species waiting
for lunch in deeper water.

"What's fascinating," explained Borowski, "is the zonation
you see between the species on these big minus tides. The competition
for space in the infralittoral fringe, the midzone, is intense. In 500
million years these species have never had a day off. Somehow they've
managed to achieve a remarkable level of symbiotic balance. You have to
take care of your neighbor because she's probably your next meal."

Successful species have flourished by developing specializations that
enable them to travel between zones. The hard-shelled chitons and soft-shelled
crabs, for example, have rigid exoskeletons that protect them from drying
out when the receding tide leaves them exposed to terrestrial elements
like wind and sun. Creatures living in the deeper regions, such as anemones
and sponges, have soft, flexible bodies that easily absorb the ceaseless
pounding of the waves. Sea stars, the alpha predator of the laminaria
zones, are completely dependent on the smorgasbord of infralittoral-fringe
protein for their survival. In other words, they always go out to dinner.
The keystone species in their restaurant of choice also happens to be
the most prolific progenitor, the common mussel. Although the mussel and
the star have evolved in different environments, their common survival
is linked, like the robin and the worm.

"In a healthy community of mussels, we'll find 7,000 individuals
per square meter," says Borowski. "Every one of those little
guys filters microbic proteins from 7.5 liters of seawater per hour. That's
14,000 gallons of filtered water per hourfor one tiny community
of mussels. Now, multiply that by a couple of hundred million years."

Those kind of numbers give me vertigo. Truth be told, I was the accidental
tourist who had always viewed tidal zones as a kind of evolutionary skid
row, a waste bin for genetic castoffs and derelicts. My long-overdue comeuppance
was at hand. Borowski pointed at a fleshy, golden-colored invertebrate
in the well of his palm.

"This little guy has a notochord as a larva, but he loses it when
he becomes an adult. . . ."

"What's a notochord?" I interrupted.

"A spinal cord," said Borowski, "vertebrae. I have the
honor of introducing you to your distant cousin, Mr. Tunicate, better
known as a sea squirt."

Marine zoologists estimate that 90 percent of the world's oceans
are biological deserts. The remaining 10 percent are home to more than
90 percent of all living creatures on our planet. At the edges of those
oceans, in a primordial world that is neither land nor sea, the first
ticks of biological time were measured in the amorphous throbbing ectoplasm
of our planet's first living cells. A billion years later the ebb and
flow of the tides are still the gods that rule here. Everybody eats, everybody
has sex, and everybody dies. But the intertidal zone is a great deal more
than a smorgasbord of protein, note Edward Ricketts, Joel Hedgpeth, and
Jack Calvin, authors of the seminal work Between Pacific Tides.
It is the testing ground for species, the giant mixing bowl of life, in
which precise and perfect adaptation to the fierce press of elements has
been the indispensable ingredient for survival for hundreds of millions
of years. Myriad life-forms that flourished in this harsh environment
in the Cambrian Era, 500 million years ago, are still with us today.

"Relatives of every major group of invertebrates on the planet can
be found in a single tidepool," explained Borowski, hovering over
a community of bright pink cnidaria, or anemones. "It's all here.
We know where life started."

In the Precambrian Era the only sounds on our planet were those of wind
against rock, water against sand. The essential building blocks of lifehydrogen,
oxygen, nitrogenwere coming together in the intertidal zone. Fossil
records show that sponges and jellyfish, worms of countless sorts, snaillike
mollusks, and a host of arthropodal ancestors to the crab emerged biologically
whole in the Cambrian. To get a better sense of time on this scale, hop
into your car and drive about three miles. One giant pace back from your
car's front bumper represents the entire anthropological time line of
Homo sapiens. By contrast, life began forming in tidepools half
a mile back in the rearview mirror. All these years later, give or take
a million, the fact that the salinity of my blood, of my sweat and tears,
is the same as the primordial soup sloshing about in these tidepools,
is as imponderable as galaxies glimpsed by Hubble, and as sobering as
a church picnic.

Slam a fist
into your open palm, over and over again, while standing in a hurricane
in February, and you have life in a tidal zone.

Yet, as I scramble from one basalt pool to the next in a state of wide-eyed
wonder, I know from research and observation that the 54,000 miles of
saltwater shoreline in the United States is under constant assault from
a rogues' gallery of the usual suspects: deforested watersheds, shoreline
developments, coastal erosion, oil spills, and pollutants of every kind.
Pesticides, herbicides, and the ubiquitous nitrates of agricultural fertilizers
lead the ceaseless charge. There is no longer any question, says Jane
Lubchenco, a world-renowned zoologist at Oregon State University, that
the rates, scales, and kinds of changes occurring in all of the earth's
ecosystems are "fundamentally different from those at any other time
in history."

In the past five years marine scientists have underscored these findings
by identifying dozens of new "dead zones" in the world's oceansregions
where low to no oxygen disrupts normal life processes. One of the largest
of those zones begins at the mouth of the Mississippi River and fans out
to cover thousands of square miles of the Gulf of Mexico.

In a report in Science, Lubchenco and her colleagues warned that
coastal wetlands have been altered over large areas and that "50
percent of mangrove ecosystems globally have been transformed or destroyed
by human activity." Moreover, they added, a planetwide increase in
harmful algal blooms in coastal ecosystems "suggests that human activity
has affected the base as well as the top of the marine food webs."
Today Lubchenco speaks of the global challenge of making a transition
to sustainability across all ecosystems. All of the ways we're changing
the planettransforming land, modifying the climate, overfishing
oceansare "due to the way we use resources and generate waste,
as well as the increasing number of people on the planet. All of those
things are acting together to disrupt the ecosystems of the planet that
provide life support for everything on earth."

Still, here on the Oregon coast, the intertidal zone can be explored
in a pristine state. When the sea pulls back her skirts at the base of
Yaquina Head, what's revealed is a world of spectacular beauty. Perched
on a ledge that was under 15 feet of seawater just hours ago, I watch
a tiny crab emerge from its rocky nook and take a look around. Its neighbors,
a colony of pink anemones, have closed against wind and light like the
iris of an eye. Voracious dog whelks have set about drilling holes into
the calcified fortresses of barnacles, sucking the rich protein through
tiny holes. Young crabs scavenge the shallow pools for a quick meal, and
limpets, periwinkles, and chitons cling to overhanging ledges. As purple
urchins and nudibranchs doze in the sun, we humans dart from one pocket
universe to the next, announcing our discoveries with hurried amazement.

At the tidal swing's nadir, Borowski lets out a whoop from the edge of
the surf. He has found what he has come for, a rare sunflower star, the
most bashful member of the peripatetic echinoderms. If you are fortunate
enough to see a sunflower star, look quickly, because a glimpse of this
shy creature is also a signal from the moon and the sun that they have
lost their grip on the ocean. In minutes the returning waves will chase
us back to the cobbled beach and reclaim the deepest pools. There, in
the timeless embrace of our planet's amniotic fluid, the most reclusive
and exotic citizens of the intertidal zone will remain beyond our reach
until the next "monster minus" event, sometime next year. As
the silence roars around us, we gather in little knots and gaze in wonder
as the crucible of life disappears beneath the gossamer flux of the sea,
leaving us high and dry. And breathless. Dusted with awe.

PAUL VANDEVELDER's work has appeared in magazines and newspapers
around the world. His new book, Coyote Warrior (Little Brown),
which chronicles the 200-year story of the Mandan-Hidatsa family that
sheltered Lewis and Clark during the winter of 1805, is due out in August.

The
intertidal zone is that narrow band of coastline between the highest
high tides and the lowest low tides. Cubic yard for cubic yard,
this ecosystem is the richest source of minerals and nutrients on
earth. Each wave serves up a stew of plankton and algae that feeds
mussels and barnacles; they, in turn, feed crabs, urchins and anemones,
sponges and stars. Creatures in the highest zones take a constant
pounding from wind and sea. (Slam a fist into your palm, over and
over, while standing in a hurricane in February, and you have life
in a tidal zone.) At the other end of the spectrum, the creatures
in the lowest pools must be ever vigilant. If they get caught outside
of their home zone by an outgoing tide, they will almost certainly
die. A big spring "minus tide" will reveal the five main
intertidal zones.

P.V.

Splash
Zones: This is where you are probably standing as you wait for
the tide to go out. Take a close look. You are likely to find yourself
in the company of periwinkles, a kind of snail that thrives on lichens
just beyond the reach of the highest tides. This, the uppermost
tidal zone, is seldom covered by the ocean. Terrestrial animals
and birds thrive here if they can tolerate an occasional dousing.
It is the most marginal and nutrient-poor part of the tidal-zone
ecosystem.

Mid-tide
Zones: Most residents of this zone, such as barnacles,
limpets, crabs, and snails, have developed hard shells for protection.
Prey and predator are never far apart here. Rock whelks drill tiny
holes into the shells of barnacles, squirting digestive juice into
the cavity, then sucking out the contents. Some common residents
of this part of the intertidal zone are red, green, and brown algae,
periwinkles, acorn barnacles, lichens, finger limpets, emarginate
whelks, and turban snails.

High-tide
Zones: This is where the action is. It is also the deepest
zone exposed by an average tide. Many creatures from neighboring
zones feast here among the dense clusters of blue mussels, limpets,
sponges, and common anemones, whose flowerlike tentacles sting and
paralyze small fish. Their jellylike bodies easily absorb the punishment
of the pounding surf, while their neighbors the sea stars (starfish)
have a system of internal hydraulics that allows them to suck water
through tubelike feet, creating sufficient suction to cling to rocks
in the heaviest weather. Other creatures here are goose-neck barnacles,
purple stone crabs, hermit crabs, ocher sea stars, and sponges.

Low-tide
Zones: The animals that thrive here can tolerate only limited
exposure to our atmosphere. There are many exotic creatures to be
found in the low zone, but they will require careful searching.
Spiny purple sea urchins are common in the deepest part of the tidepool.
The most exotic residents are the nudibranchs (nudi = naked,
and branch = gill). These small, brightly colored
creatures resemble slugs, and it takes some doing to find them,
but they are well worth the effort. Nudibranchs are carnivores that
feast on sponges and anemones. Here you will also encounter sculpins,
giant green anemones, keyhole limpets, gumboot and mossy chitons,
and crabs.

Sub-low
Zones: This
zone is seldom exposed to the air. However, its occupants are clearly
visible during a strong minus tide. If you are lucky, you will glimpse
the exotic sunflower star. This brainless, headless animal can have
5 to 24 arms and more than 15,000 tubelike feet. Sunflower stars
have been found at depths of 1,500 feet. They live beside giant
green sea anemones, which have thousands of nematocysts on their
arms. The nematocysts paralyze sculpins and crabs, this giant’s
favorite meals.